Facebook and Instagram announced Wednesday they are tightening restrictions on their sites to prevent people from selling or trading guns illegally.

As a result of the company's new restrictions, minors cannot view posts concerning gun purchasing or gun trades. When users create a post advocating the private sale of guns, Facebook will send a message to the poster reminding him or her to obey regulations and laws, according Jessica Guynn at the Los Angeles Times.

Facebook also now requires pages that publicize the private sale of regulated services and goods to add warnings to remind users to obey laws and regulations, writes Guynn.

Gun control lobbyists, including New York Attorney General Eric Schneiderman, Sandy Hook Promise and Michael Bloomberg's Mayors Against Illegal Guns, have been advocating for Facebook to change its policies for months, reports Forbes.

Schneiderman was pleased that Facebook and Instagram, a company owned by Facebook, are creating new regulations.

"Responsible social media sites know that it is in no one’s interest for their sites to become a 21st century black market in dangerous and illegal goods that place our families and communities at risk,” said Schneiderman in a statement, per Forbes. "I congratulate Facebook and Instagram for taking these simple, common-sense steps to protect the safety and security of their users, and encourage other social media sites to follow their lead."

"American moms are gratified that Facebook and Instagram have agreed to take meaningful steps to prevent illegal gun sales to children and dangerous people on its platforms," Watts said in a statement to CBS News. "We are happy that these companies listened to American mothers and we believe these changes are a major step toward making sure people who buy or sell guns on their platforms know the law, and follow it."

Others are upset that Facebook and Instagram cracked down on gun sales and trades.

"There is no smoking gun here of big groups of Facebook users doing something wrong that requires some regulation," said Stanton McCandlish in a USA Today article. "But Facebook is a private company. I guess if they want to have restrictive policies that alienate users, they can do that."

The Facebook page of the Utah Gun Exchange is seen Monday, Dec. 24, 2012. Facebook and Instagram announced Wednesday they are tightening restrictions on their sites to prevent people from selling or trading guns illegally because of the efforts of numerous pro-gun control groups.